The field of this invention is a subsurface well apparatus and method.
The practice of using controlled subsurface devices in production tubing of producing wells to close the bore of the production tubing to flow for preventing a well blowout is well known in the art. Sand and other abrasives flowing through the devices with the produced hydrocarbons eroded or damaged the device and frequently made the device inoperative. Previously it has been necessary to utilize a wire line tool or pull a portion of the production string to replace a controlled subsurface device. The lost production as well as the cost of the special crews and equipment made replacement an expensive operation.